Posted: Sat Dec 19, 2009 5:59 pm Post subject: Post of the Week: Can sinemet slow disease progression?
Does levodopa slow the progression of Parkinson disease?
Levodopa has changed the lives of millions of Parkinson’s disease patients. Patients now live longer, and have more rewarding lives with much less and even slower progressing disability in some cases (when compared to the pre-levodopa era). The positive effects of levodopa can be felt for many years, however, levodopa is not a cure. Levodopa does not relieve all symptoms of Parkinson’s disease. Additionally, not all patients respond to levodopa with consistent results, although most respond very well. Levodopa may also have side effects—and some patients in the Parkinson’s disease population seem to be more susceptible to side effects than others---so therapy needs to be tailored to the individual.
As to whether levodopa slows disease progression in Parkinson’s disease, the jury is still out. The data are conflicting. We have a large clinical trial that showed that those on the highest dose of levodopa had the best motor function, and the slowest decline. The imaging arm of that study however revealed that the basal ganglia (the part of the brain that is sick in Parkinson’s disease) had significantly less amounts of surviving dopaminergic brain cells. We have been unable to definitively explain this discrepancy between the clinical finding and the imaging results. Most authorities believe however that levodopa does not affect disease progression, but this remains a controversial topic. More research may shed light on this controversy (Clarke 2004; Olanow 2004; Castro, Valldeoriola et al. 2005; Fahn 2005; Fahn 2006; Fahn 2006; Suchowersky, Gronseth et al. 2006; Chan, Nutt et al. 2007; Schapira 2007; LeWitt and Taylor 2008).
Hubert H. Fernandez